Before discussing the limitations of performance testing with manual testing, lets discuss Why Performance / Load Test is required?
Load/Performance Testing is required to expose bugs that do not surface during Functional Tests Ex. Memory leaks, buffer overflows. To Assure Performance & functionality under real-time conditions. To locate potential problems before deployment in production. To establish a baseline for future regression testing.
To verify and prove the soundness of Infrastructure. To collect metrics on various performance measures.
Manual performance testing is not feasible for testing systems which must support tremendous loads. Following are the Load testing Limitations with Manual Testing:
1. Generate enough load to perform testing.
2. Obtain sufficient testing personnel (Users) and host machines.
3. Synchronize Users.
3. Measuring Test results.
4. Repeatability of tests after identifying & fixing bottlenecks.
Related article – LoadRuner Tips
A Must read – Art of Application Performance Testing